Bill Gates and Warren Buffett didn't want to be best friends. They didn't even want to meet.

A Business Insider story details the friendship between Gates and Buffett — the second- and third-richest people in the world, respectively.

It all began when Gates' mother invited the late Washington Post reporter Meg Greenfield and Buffett to her home back in 1991. Gates didn't want to take a day off work, but he did want to meet the late Post publisher turned The Post movie subject Katharine Graham, who was coming as well.

Buffett simply recalled wondering, “How long do we have to stay to be polite?”

But after some small talk imagining how they would've built IBM if they were at the helm, Gates and Buffett stuck together.

Since then, the multi-billionaires have swapped books, tried out mattresses, and pledged to donate more than half of their fortunes via The Giving Pledge. You know, just your normal, everyday best friend things. Take a closer look at the pair's 27-year friendship at Business Insider. Kathryn Krawczyk